Small talk is definitely easier after a few drinks. Anything goes, really. Drinking, fine dining, gambling, other punters, other WGs, work, the human condition, fear of death, traffic in London, video games, Brexit, Trump.
If you don't feel like making small talk with WGs, just don't. You aren't paying her £100+ an hour just so you can talk to her about Nietzsche or monetary policy -- if you ever get bored of the chitchat, just tell her to suck your dick.